Shedding light on intracoronary pathophysiology

There is a new player in the field of interventional cardiology. It is optical coherence tomography (OCT), an imaging modality analogous to intravascular ultrasound (IVUS), but using light instead of sound. The paper by Yonetsu et al in this issue of the IJC is therefore of timely interest, as an illustration of where OCT evaluation of coronary pathophysiology is at present, and what the future might hold.

[Effects of electroacupuncture of "source-" plus "collateral-" acupoints on the cardiac function and myocardial enzymes in acute myocardial ischemia rabbits]

OBJECTIVE

To observe the effects of electroacupuncture (EA) of "Source-" + "Collateral-" acupoints ["Shenmen" (HT 7) + "Zhizheng"(SI 7)] and single acupoints "Neiguan"(PC 6) and HT 7 on cardiac function and myocardial enzymes in acute myocardial ischemia (AMI) rabbits.

METHODS

Sixty Chinchilla rabbits were randomized into normal control, model, Shenmen (HT 7), Neiguan (PC 6), HT 7 + SI 7 groups, with 8 rabbits in each. AMI model was duplicated by occlusion of the anterior descending branch of left coronary artery under anesthesia. EA (2 Hz,1 mA) was applied to acupoints HT 7, PC 6,and HT 7 + SI 7 for 10 min. The maximum ascending rate (+ dp/dt max) and maximum descending rate (-dp/dt max) of the left ventricular pressure (LVP) were recorded by using PowerLab System. Serum lactate dehydrogenase (LDH) and creatine kinase MB (CK-MB) contents were detected with chromatometry.

RESULTS

Serum LDH and OK-MB contents increased significantly in model group than in normal control group (P < 0.01). Compared with model group, serum LDH and CK-MB contents decreased remarkably in PC 6, HT 7 and HT 7 + SI 7 groups (P < 0.01, P < 0.05), and the effects of HT 7 + SI 7 group were significantly superior to those of PC 6 and HT 7 groups in lowering serum LDH and CK-MB levels (P < 0.01, P < 0.05). Compared with the normal control group, + dp/dt max lowered significantly and -dp/dt max increased markedly in the model group (P < 0.01), while compared with the model group, + dp/dt max increased obviously and -dp/dt max decreased significantly in the three EA groups (P < 0.01, P < 0.05). The effects of HT 7 + SI 7 group were markedly superior to those of HT 7 and PC 6 in raising + dp/dt max and lowering -dp/dt max (P < 0.05, P < 0.01), and those effects of PC 6 group were evidently better than those of HT 7 group (P < 0.05, P < 0.01).

CONCLUSION

EA of "Source-" + "Collateral-" aoupoints (HT 7 + SI 7), HT 7 and PC 6 has a positive effect in improving changes of cardiac function and in lowering serum LDH and CK-MB contents in AMI rabbits, and the effect of EA of HT 7 + SI 7 is superior to that of EA of single acupoint.

Long-term prognostic value of cardiac troponin I and T versus creatine kinase-MB mass after cardiac surgery in low-risk patients with stable symptoms

The long-term prognostic value of elevated cardiac biomarkers after elective cardiac surgery is not clear. The recent guidelines for diagnosing perioperative infarcts have advocated the use of similar thresholds for creatine kinase-MB (CK-MB) mass and the cardiac troponins. However, few previous data are available comparing these biomarkers after cardiac surgery, and it is not clear whether postoperative elevations of the troponins can be treated the same as elevations of CK-MB. We sought to compare the prognostic value of the cardiac troponins versus the CK-MB mass after elective cardiac surgery in low-risk patients with stable symptoms. A total of 204 consecutive patients undergoing cardiac surgery were included in the final analysis. Blood samples were drawn just before and 1 to 3 and 4 to 8 hours after the procedure, and every morning for 3 days thereafter. Patients with elevated baseline values were excluded. Using a cutoff value of 5 times the reference, patients with high and low values (controls) of CK-MB mass, cardiac troponin T (cTnT) and cardiac troponin I (cTnI) were compared. The median follow-up time was 92 months. None developed new Q-waves on the electrocardiogram. The incidence of the composite end point of all-cause mortality, readmission for acute coronary syndrome, and target vessel revascularization in the high CK-MB group was 41.2% compared to 21.8% in the controls (p = 0.004). The corresponding values for cTnT were 33.3% and 20.4% (p = 0.075) and for cTnI were 27.0% and 34.6% (p = 0.237). The p value in the isolated coronary artery bypass grafting subgroup (n = 156) was p = 0.043 for CK-MB, p = 0.137 for cTnT, and p = 0.795 for cTnI. High CK-MB (p = 0.001), ejection fraction (p = 0.002), and body mass index (p = 0.010) were the only variables independently related to reduced event-free survival. No such relation was found for high cTnT and cTnI. In conclusion, CK-MB was superior to the cardiac troponins (values > or =5 times the reference) in predicting long-term event-free survival after elective cardiac surgery in low-risk patients with stable symptoms undergoing coronary artery bypass grafting and/or valve surgery.

Cardiotoxic effects of Loxosceles intermedia spider venom and the recombinant venom toxin rLiD1

Loxosceles spider bites cause many human injuries worldwide. Injections in mice of whole Loxosceles (L.) intermedia venom or a recombinant toxin (rLiD1) produce systemic symptoms similar to those detected in envenomed humans. This animal model was used to characterize the effects of Loxosceles intermedia venom in cardiac tissues. L. intermedia antigens were detected by ELISA in kidney, heart, lung and liver of experimentally envenomed mice. In addition, rLiD1 binding to cardiomyocytes was demonstrated by immunofluorescence and confocal microscopy. Furthermore, isolated perfused heart preparations and ventricular cardiomyocytes from envenomed mice showed heart function impairment, and a significant increase of I(Ca,L) density and intracellular Ca(2+) transients, respectively. Thus, L. intermedia spider venom, as shown through the use of the recombinant toxin rLiD1, causes cardiotoxic effects and a protein from the sphingomyelinase D family plays a key role in heart dysfunction. Thus, L. intermedia spider venom and the Loxtox rLiD1 play a key role in heart dysfunction.

Brain natriuretic peptide mediates the effect of creatinine clearance on development of left ventricular systolic dysfunction in patients with acute coronary syndrome

INTRODUCTION

There are only limited data about the role of renal function in the development of left ventricular systolic dysfunction in patients with an acute coronary syndrome (ACS). We sought to investigate whether renal insufficiency is an independent predictor for systolic dysfunction among patients who had an ACS.

METHODS

During 2006-2007, 814 consecutive patients who presented with an ACS event were enrolled prospectively; of these, 284 men (65 ± 14 years) and 71 women (71 ± 12 years) developed left ventricular systolic dysfunction (ejection fraction <40%), 306 men (64 ± 12 years) and 78 women (67 ± 10 years) had preserved left ventricular systolic function (ejection fraction >50%), while the rest of the patients (n=75), with ejection fraction between 40-50%, were excluded from this analysis. Creatinine clearance rates were estimated by the Cockcroft-Gault formula.

RESULTS

Eight percent of patients presented with severe and 30% with moderate renal dysfunction. Multiple logistic regression analysis revealed that a 10-unit increase of creatinine clearance levels decreases the odds of developing left ventricular systolic dysfunction by 8% (95%CI per 1 unit: 0.986-0.998), after controlling for potential confounders. Moreover, brain natriuretic peptide levels were inversely correlated with creatinine clearance (r=-0.378, p<0.001). When brain natriuretic peptide was entered into the model, creatinine clearance was not associated with left ventricular systolic dysfunction (OR=0.997, 95%CI 0.989-1.005).

CONCLUSIONS

The role of renal insufficiency in the development of left ventricular systolic dysfunction seems to be partially explained by plasma brain natriuretic peptide levels, suggesting a potential pathophysiological mechanism. Thus, patients with impaired creatinine levels and elevated brain natriuretic peptide levels should receive more aggressive medical care, as they are prone to developing left ventricular systolic dysfunction.

Assessment of differential leukocyte count in patients with acute coronary syndrome

OBJECTIVE

To assess the predictive ability of leukocyte subtypes for mortality in patients with acute coronary syndrome (ACS).

METHODS

One hundred and thirty three consecutive patients of ACS wer assessed in the study and were followed up for one year. Diagnosis was based on clinical characteristics and the laboratory data. The total leukocytes and its subtypes were counted by Sysmex automated cell counter. The predictive ability for death of total count of leukocytes, neutrophils, lymphocytes and monocytes was assessed using Cox regression analysis.

RESULTS

Univariate analysis revealed higher prevalence of total leukocytes (HR= 1.001, p < or = 0.001) and its subtypes, neutrophils (HR = 1.001, p < or = 0.001) and monocytes (HR 1.006, p < or = 0.001), in patients of ACS. In multivariate modeling, after entering standard coronary risk factors, count of total and differential leukocytes-neutrophils, lymphocytes, monocytes and cardiac biomarkers CK-MB, Trop I; the monocyte count (hazard ratio [HR] 1.004, CI 1.002-1.006, p < 0.0001) was found to be independent predictor for ACS. A significance correlation between monocyte count and CK-MB, representing extent of myocardial damage, was also seen (r = 0.301, p < 0.0001).

CONCLUSION

The increase in monocyte count is an independent predictor of death and prognostic marker of the extent of myocardial damage in patients with ACS.

[Protective effect of fosinopril sodium pretreatment combined with ischemic postconditioning on rat heart underwent myocardial ischemia/reperfusion injury]

OBJECTIVE

To investigate the effects of fosinopril sodium pre-treatment combined with ischemic postconditioning on rat serum and myocardial oxidative stress and proinflammatory cytokines post ischemia/reperfusion.

METHODS

Sixty Sprague-Dawley rats were randomly divided into sham group (n = 15), ischemia/reperfusion group (30 minutes in situ occlusion of the left anterior descending artery followed by 1 hour reperfusion, n = 15), IPoC group (30 minutes occlusion of the left anterior descending artery followed by 3 cycles of 10 seconds of reperfusion/10 seconds of ischemia before 1 hour reperfusion, n = 15) and fosinopril sodium group [pretreated with fosinopril sodium (0.9 mg×kg(-1)×d(-1) for 14 days) followed by IPoC protocol at 2 h after the last gavage, n = 15]. The arterial blood and heart samples were extracted after 1 hour reperfusion. Serum CK-MB and cTnT levels were detected by colorimetric method, myocardial infarction size was measured by nitrotetrazolium blue chloride staining, SOD content was examined by colorimetric method, MDA content was detected using thiobarbituric acid method, serum levels of Interleukin-1α (IL-1α), Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were examined by radioimmunoassay, IL-1α, IL-6 and TNF-α levels of myocardial tissue were detected by ELISA.

RESULTS

Compared with I/R group, myocardial enzymes and infarction size were significantly decreased (P < 0.05, P < 0.01), serum SOD content was increased and MDA content was decreased (all P < 0.01), serum and myocardial levels of IL-1α, IL-6 and TNF-α were significantly reduced (P < 0.05, P < 0.05, P < 0.01) in IPoC group. Compared with IPoC group, fosinopril sodium pretreatment further reduced infarction size and myocardial enzyme CK-MB (P < 0.05), increased SOD content (P < 0.05) while reduced serum IL-6 and myocardial tissue TNF-α (P < 0.05, P < 0.01).

CONCLUSION

Pretreatment with fosinopril sodium enhanced the protective effect of IPoC on rat myocardium underwent I/R injury, possibly by reducing oxidative stress and early inflammatory reaction.

The use of cardiac biomarkers in detection of cardiotoxicity associated with conventional and high-dose chemotherapy for acute leukemia

AIM

Monitoring of cardiotoxicity of conventional and high-dose chemotherapy (HD-CT) with multiple biomarkers of cardiac injury - glycogen phosphorylase BB (GPBB), heart-type fatty acid binding protein (H-FABP), cardiac troponins (cTnT, cTnI), creatine kinase MB (CK-MB mass), myoglobin.

METHODS

A total of 47 adult acute leukemia patients were studied - 24 patients treated with conventional CT containing anthracyclines (ANT) and 23 patients treated with HD-CT (myeloablative preparative regimen) followed by hematopoietic cell transplantation (HCT). Cardiac biomarkers were assessed prior to treatment (before CT/HD-CT), after first CT with ANT, after last CT with ANT in the first group, after HD-CT and after HCT in the second group. Values above the reference range were considered elevated.

RESULTS

Before CT/HD-CT, all biomarkers of cardiac injury were below the cut-offs in all patients. GPBB increased above the cut-off (7.30 microg/L) in 4 (16.7%) patients after first CT and in 5 (20.8%) patients after last CT with ANT. GPBB increased above the cut-off in 5 (21.7%) patients after HD-CT and remained elevated in 5 (21.7%) patients after HCT. CTnI became elevated (above 0.40 microg/L) in 2 (8.3%) patients after first and last CT with ANT. Both patients with cTnI positivity had elevated GPBB. Other tested biomarkers remained below the cut-offs during the study.

CONCLUSION

Our results suggest that GPBB could become a sensitive biomarker for detection of acute cardiotoxicity associated with conventional CT containing ANT and HD-CT followed by HCT. The predictive value for development of cardiomyopathy in the future is not known and should be evaluated during a prospective follow-up. Based on our data, a larger prospective and multicenter study would be most desirable to define the potential role of new circulating biomarkers in the assessment of cardiotoxicity in oncology.

Surface plasmon resonance aided electrochemical immunosensor for CK-MB determination in undiluted serum samples

This article presents a simple chronoamperometric immunosensor for the quantitative assessment of creatine kinase MB (CK-MB) in 50 microL undiluted serum samples. The immunosensor consists of gold working and counter electrodes patterned onto a glass chip by thin-film photolithography and an external Ag|AgCl reference electrode. The detection limit (DL) of the chronoamperometric method is 13 ng mL(-1) (DL = 2xRMSD/S, where RMSD is the residual mean standard deviation of the measured points around a calibration curve with a slope of S). In spiked serum samples, the response was linear up to 300 ng mL(-1) of CK-MB. A surface plasmon resonance (SPR) system with simultaneous electrochemical detection (EC-SPR) aided the development of the sandwich immunoassay. Real-time monitoring of the SPR signal was used to optimize the capture antibody immobilization, CK-MB and detection antibody binding, as well as to minimize the nonspecific adsorption of serum proteins to the sensor surface. The detection antibody has been labeled with alkaline phosphatase (ALP) enzyme for sensitive electrochemical detection. ALP catalyzes the hydrolysis of ascorbic acid phosphate and generates ascorbic acid, which is measured chronoamperometrically. The electrochemical immunoassay for CK-MB was less sensitive to nonspecific adsorption related interferences, had a better detection limit, and required a lower volume of sample than the SPR method.

[The change of thioredoxin system in myocardial tissue of type 2 diabetic rats undergoing myocardial injury]

The aim of the present study is to investigate the change of thioredoxin (Trx) system in myocardial tissue of type 2 diabetic rats after myocardial injury and the underlying mechanism. Adult Sprague Dawley rats were randomly divided into two groups: normal control (NC) group and diabetes (DM) group. Rats in DM group were subjected to high-sugar, high-fat diet and streptozotocin (STZ) injection. Rats in NC group were only given normal diet and equal amount of citric acid buffer injection. At week 1, 2, 4, 12, 21 after STZ injection, plasma glucose concentration and the concentrations of insulin, creatine kinase MB (CK-MB), cardiac troponin I (cTnI) in serum were measured. Myocardial Trx and thioredoxin reductase (TR) activities, as well as caspase-3 activity, were determined by respective assay methods. Protein and mRNA levels of Trx, TR, Trx interacting protein (TXNIP) were determined by Western blot and real time PCR, respectively. The results showed that type 2 diabetic rat model was successfully established at week 1 after STZ injection, and myocardial injury was induced from week 2. Moreover, caspase-3 activity was significantly increased at week 4, 12 in diabetic rats. The activities of myocardial Trx and TR in diabetic rats was decreased from week 2, and continually aggravated as the disease developed. Compared with those in NC group, the mRNA levels of Trx1, Trx2, TR1, TR2 in DM group decreased at week 4, and then increased in week 12. In DM group, the protein levels of Trx1, Trx2, TR1 and TR2 increased significantly at week 12. The mRNA expressions of myocardial TXNIP in diabetic rats were significantly increased at week 4, 12, 24 and protein expression was increased at week 12. These results suggest diabetes can decrease myocardial Trx, TR activity, inducing myocardial cell apoptosis and heart injury. The inhibitory effect of diabetes is mainly associated with TXNIP up-regulation and Trx nitration.

[Predictive value of human fatty acid binding protein for myocardial ischemia and injury in perioperative period of cardiac surgery]

OBJECTIVE

To evaluate the value of human fatty acid binding protein (h-FABP) in predicting myocardial ischemia and injury in the perioperative period of cardiac surgery, we observed the dynamic changes of h-FABP in perioperative period of patients underwent coronary artery bypass grafting and ventricular septal defects repairing surgery, and evaluated the relationship of h-FABP and ischemia modified albumin (IMA), CK-MB, cTnI.

METHODS

Patients underwent coronary artery bypass grafting (n=30) and ventricular septal defect repairing (n=30) surgery between February 2008 and December 2008 were included in this study. Venous blood sample was obtained at preoperative, aortic clamping, aortic unclamping of 10 min, 2 h, 6 h, 12 h, 24 h for the measurements of h-FABP, IMA, cTnI and CK-MB.

RESULTS

h-FABP and IMA changed in the same way at various examined time points, h-FABP changes also paralleled cTnI and CK-MB changes, h-FABP peaked early during myocardial ischemia and injury and returned to baseline level at 2 h post myocardial ischemia and injury. Linear correlation analysis showed that the peak value of h-FABP was positively correlated with IMA, CK-MB and cTnI in both CABG group (r = 0.948, 0.964 and 0.961, P < 0.05) and in the VSD group (r = 0.986, 0.978 and 0.957).

CONCLUSIONS

h-FABP is an early diagnostic parameter reflecting perioperative myocardial ischemia and injury in cardiac surgery. Quantitative h-FABP monitoring could predict the severity of myocardial ischemia and injury early during cardiac surgery.

Perioperative brain natriuretic peptide in off-pump coronary artery bypass

BACKGROUND

During the last decade brain natriuretic peptide (BNP) has been recognized as a useful marker for acute and chronic left ventricular dysfunction. The present study was designed to evaluate the clinical relevance of BNP before and after off-pump coronary artery bypass (OPCAB).

METHODS

One hundred and twelve patients undergoing primary OPCAB were divided into two groups by preoperative BNP levels (group A, BNP < or = 100 pg/ml and group B, BNP > 100 pg/ml). Levels of BNP and MB isoenzyme of creatine kinase (CK-MB) were measured preoperatively, 6 hours and 1 day post-operatively. Echocardiographic and clinical data were collected.

RESULTS

Patients in group A had smaller perioperative left ventricular end-diastolic dimensions (LVEDD) and greater left ventricular ejection fractions (LVEF) compared to group B (P < 0.05). Levels of BNP and CKMB increased postoperatively in both groups (P < 0.01). However, there was no relationship between postoperative BNP and CKMB at any time point. Logistic regression analyses showed that a preoperative BNP level > 100 pg/ml was an independent risk factor for ventilation > 24 hours (odds ratio, OR = 13.33; 95% CI: 1.42-125.03) and ICU stay > 72 hours (OR = 3.01; 95% CI: 1.09-8.33).

CONCLUSION

The baseline BNP level correlated with preoperative ventricular function and longer durations of ventilation and hospital stay after OPCAB. BNP increased early after operation. However, postoperative BNP did not correlate with myocardial injury or clinical results after OPCAB.

Legionnaires' disease mimicking swine influenza (H1N1) pneumonia during the "herald wave" of the pandemic

BACKGROUND

New York area hospitals were hit hard by the swine influenza (H1N1) pandemic in spring and summer 2009. During a pandemic, the initial cases may be difficult to recognize, but subsequent clinical diagnoses were relatively straightforward, given the high volume of cases and their typical clinical presentation. Swine influenza pneumonia presents as an influenza-like illness (ILI) with dry cough, fever >102 degrees F and myalgias. A variety of other viral pneumonias, eg, cytomegalovirus, human parainfluenza virus 3 (HPIV 3), and adenovirus, as well as bacterial community-acquired pneumonias (CAPs) that may present with some of the clinical and laboratory features of H1N1 pneumonia. Most adults admitted to hospitals with ILIs during the pandemic had, in fact, definite or probable H1N1 pneumonia. The Infectious Disease Division at Winthrop-University Hospital developed a diagnostic weighted point score to identify probable H1N1 cases in hospitalized adults with rapid negative influenza diagnostic tests (RIDTs).

METHODS

We present a case of an elderly male who presented with an ILI and negative RIDTs during the H1N1 pandemic. He was admitted with a diagnosis of possible H1N1, and placed on influenza precautions and oseltamivir. Although the patient had features consistent with H1N1 pneumonia, Legionnaires' disease was included in the differential diagnosis because of his elevated serum ferritin levels. A Legionella urinary antigen test was positive for Legionella pneumophila (serogroups 01-06).

RESULTS

The peak seasonal incidence of sporadic Legionnaires' disease occurs in the summer and fall. Even in the midst of a pandemic, clinicians should be on the alert for other infectious diseases that may mimic H1N1 pneumonia. In our experience, the best way to differentiate H1N1 from ILIs or other bacterial CAPs is through the Winthrop-University Hospital Infectious Disease Division's diagnostic weighted point score system for H1N1 pneumonia or its rapid simplified version, ie, the diagnostic swine influenza triad. Legionnaires' disease is the atypical CAP pathogen most likely to mimic H1N1 pneumonia.

CONCLUSIONS

Based on this and other nine cases at our institution during the "herald wave" of pandemic, we conclude that Legionnaires' disease may mimic swine influenza (H1N1) pneumonia.

[Plasma levels of N-terminal pro-brain natriuretic peptide and glycogen phosphorylase isoenzyme BB in neonates with asphyxia complicated by myocardial injury]

OBJECTIVE

To investigate the changes and the clinical significance of N-terminal pro-brain natriuretic peptide (NT-proBNP) and glycogen phosphorylase isoenzyme BB (GPBB) levels in neonates with asphyxia complicated by myocardial injury.

METHODS

Sixty-four neonates with asphyxia (39 mild, 25 severe) were enrolled. Of the 64 neonates, 30 had myocardial injury and 34 did not develop myocardial injury. Twenty-five healthy neonates served as a control group. Plasma levels of NT-proBNP and GPBB were measured using ELISA. Myocardial enzymes and cardiac troponin I were stimultaneously measured, and electrocardiography and chest radiographs were obtained.

RESULTS

The plasma levels of NT-proBNP and GPBB in neonates with myocardial injury were significantly higher than those in neonates without myocardial injury and in the control group (P<0.01). The neonates with severe asphyxia had significantly increased plasma NT-proBNP and GPBB concentrations compared to those with mild asphyxia and the control group (P<0.01). Spearman rank correlation analysis showed that plasma NT-proBNP level was positively correlated with plasma GPBB level in neonates with asphyxia. Plasma levels of NT-proBNP and GPBB were also positively correlated with plasma levels of CK-MB, CK and LDH (P<0.01).

CONCLUSIONS

Both NT-proBNP and GPBB can be used as biomarkers of myocardial injury in neonates with asphyxia. The measurement of plasma NT-proBNP and GPBB levels was useful in early identification of myocardial injury and severity evaluation in neonates with asphyxia.

Preventive effect of rutin, a bioflavonoid, on lipid peroxides and antioxidants in isoproterenol-induced myocardial infarction in rats

The consumption of diets rich in plant foods is associated with a reduced risk of cardiovascular diseases. This study aimed to evaluate the preventive role of rutin on lipid peroxides and antioxidants in normal and isoproterenol-induced myocardial infarction in rats. Subcutaneous injection of isoproterenol (150 mg kg−1) to male Wistar rats at an interval of 24 h for two days showed a significant increase in the activity of serum cardiac marker enzymes (creatine kinase, lactate dehydrogenase, aspartate transaminase and alanine transaminase) and a significant decrease in the activity of these enzymes in the heart. Lipid peroxidative products (thiobarbituricacid reactive substances and lipid hydroperoxides) were significantly increased and enzymic (superoxide dismutase, catalase and glutathione peroxidase) and non-enzymic (reduced glutathione and vitamin C) antioxidants showed a significant decrease in isoproterenol-treated rats. Pretreatment with rutin (40 or 80 mg kg−1) to isoproterenol-treated rats orally for a period of 42 days daily caused a significant effect. Administration of rutin to normal rats did not have any significant effect on any of the parameters studied. The results of our study show that rutin possesses antioxidant activity in isoproterenol-induced experimental myocardial infarction.

Quartiles of peak troponin are associated with long-term risk of death in type 1 and STEMI, but not in type 2 or NSTEMI patients

BACKGROUND

The prognostic value of peak cardiac troponin (cTn) in different types of acute myocardial infarction (AMI) under the universal clinical classification is unknown.

HYPOTHESIS

We tested the hypothesis that the prognostic value of cTn varies with its peak level and type of AMI.

METHODS

We studied 345 consecutive patients with AMI with mean follow-up of 30.6 months according to quartiles of peak cTn level (QPTL) and the type of AMI. The study outcomes were the major adverse cardiovascular events (MACE; composite of all causes of mortality and recurrent AMI) and the individual components of MACE.

RESULTS

The study included patients with AMI Type 1 (n = 276), type 2 (n = 54), ST-segment elevation myocardial infarction (STEMI; n = 159), and non-ST-segment elevation myocardial infarction (NSTEMI; n = 186). Overall, peak cTn level was an independent predictor of MACE (hazard ratio [HR]: 1.001, 95% confidence interval [CI]: 1.000-1.003, P = 0.01) and death (HR: 1.002, 95% CI: 1.001-1.004, P = 0.003), but not of recurrent AMI. The highest risk of MACE and death was in the highest QPTL (61.6%, P = .016 and 66.3%, P = 0.021, respectively) while the highest risk of recurrent AMI was in the lowest QPTL (83.7%, P = 0.04). Quartiles of peak cTn level were significantly associated with increased risk of MACE and death in patients with Type 1 (all P = 0.01) and STEMI (P = 0.01 and P = 0.02, respectively), but no association existed in type 2 or NSTEMI patients.

CONCLUSIONS

Overall, peak cTn predicts the risk of MACE and death but not the risk of AMI. While in Type 1 and STEMI patients, QPTL are associated with risk of MACE and death, no association exists in type 2 or NSTEMI patients.

Effect of milrinone on short-term outcome of patients with myocardial dysfunction undergoing coronary artery bypass graft: A randomized controlled trial

BACKGROUND

Myocardial dysfunction needing inotropic support is a typical complication after on-pump cardiac surgery. In this study, we evaluate the effect of milrinone on patients with ventricular dysfunction undergoing coronary artery bypass graft (CABG).

METHODS

Seventy patients with impaired left ventricular function [left ventricular ejection fraction (LVEF) < 35%] undergoing on-pump CABG were enrolled. Patients were randomized to receive either an intraoperative bolus of milrinone (50 microg/kg) or saline as placebo followed by a 24-hour infusion of each agent (0.5 microg/kg/min). Hemodynamic parameters and transthoracic echocardiographic measurement of systolic and diastolic functions were the variables evaluated.

RESULTS

Serum levels of creatine phosphokinase (CPK), the MB isoenzyme of creatine kinase (CK-MB), occurrence of myocardial ischemia or infarction, and mean duration of using inotropic agents were significantly lower in the milrinone group (p < 0.05). There were no significant differences between the two groups regarding the development of ventricular arrhythmia, duration of cardiopulmonary bypass, intra-aortic balloon pump and inotropic support requirement, duration of mechanical ventilation, duration of intensive care unit stay and mortality rate. Although mean pre-operative LVEF was significantly lower in the milrinone group, there was no significant difference between post-operative LVEFs.

CONCLUSIONS

We suggest that perioperative administration of milrinone in patients undergoing on-pump CABG, especially those with low LVEF, is beneficial.

Persistently elevated CKMB and negative troponin T in a patient at ischaemic risk with chest pain

Analytical interference in laboratory assays is not only unpredictable but also an underestimated problem. Not recognising these interferences can lead to misdiagnosis and mismanagement of patients. We present a case of a patient with chest pain and ischaemic risk factors with incongruent biochemical results. These results were discovered to be due to the presence of macro-creatine kinase (macro-CK) in vivo interfering with the CKMB activity assay.

Multicentre analytical evaluation of a new point-of-care system for the determination of cardiac and thromboembolic markers

BACKGROUND

The cobas h 232 point-of-care analyzer by Roche is the instrument successor of the Cardiac reader allowing the quantitative determination of troponin T, creatine kinase MB, myoglobin, NT-proBNP and D-dimer.

METHODS

In this study 1329 patients with acute coronary syndromes, heart failure, thromboembolic or other diseases and 945 healthy donors were assessed. Comparisons versus central laboratory methods were carried out with 2379 samples from these individuals; out of these, 1591 samples gave quantitative results within the measuring range and were included in the evaluation.

RESULTS

The point-of-care assays for creatine kinase MB, myoglobin, NT-proBNP and D-dimer were within a relative bias range of -5.9 to +6.9% compared to the laboratory assay. The troponin T assay showed a bias of -11.0% and after change of the calibration procedure of +1.9%. None of the five point-of-care assays had a relative difference between the new system and the precursor device that was higher than +5.0%. Within-series coefficients of variation of patient samples were found in a range from 4.8 to 14.8%. No significant interference was observed with lipemic, hemolytic and icteric blood or at different hematocrit values.

CONCLUSIONS

Due to its good analytical agreement with the laboratory methods and with its precursor device, the cobas h 232 system can be reliably used to support on-site decision making for cardiovascular patients in acute and non-acute settings.

Utility of placental growth factor for prediction of 30-day adverse event in emergency department population with non-ST elevation acute coronary syndrome

BACKGROUND

Placental growth factor (PIGF) belongs to the vascular endothelial growth factor family and seems to be an independent biomarker for plaque disruption, ischemia, and thrombosis. Plasma PIGF is rapidly produced in infarcted myocardial tissue during the acute phase of myocardial infarction. In this study, the relevance of PIGF was analyzed at the admission of patients with acute coronary syndrome (ACS) without ST elevation for the prognosis of fatal outcome after 30 days.

METHODS

We collected blood samples from 102 ACS patients admitted to the coronary unit with manifesting acute chest pain within the previous 12 hours and measured the levels of PIGF, high-sensitivity C-reactive protein (hsCRP), and cardiac markers: troponin T (cTnT), B-type natriuretic peptide, creatine kinase-MB (CKMB) and CK activity.

RESULTS

PIGF, troponin T, and hsCRP levels were significantly higher in non-survivors than in survivors. ROC analysis showed that PIGF had the highest area under ROC curve (AUC, 0.713), but it was not significantly different from AUCs for cTnT and hsCRP. Higher values of PIGF (>13.2 ng/L) pointed towards a higher risk of fatal outcome (HR 2.28; 95 % CI 1.21-4.76; P=0.0125). The multivariable proportional hazards analysis, which had involved other statistically significant markers of relative risk (age and gender), showed that PIGF was an independent prognostic marker (adjusted HR 2.14; 95 % CI 1.08-4.22).

CONCLUSIONS

These results confirmed that PIGF is an independent biomarker of short-term adverse outcome in patients with ACS without ST elevation and that plaque instability, represented by PIGF elevation, has an important role in the pathogenesis of future coronary events.

[The application of biochemical indexes detecting in sudden cardiac death in forensic autopsy]

Sudden cardiac death(SCD) from early myocardial ischemia is often lack of typically morphological findings and clinical manifestation, thus cases of SCD may be suspected as criminal cases. It is necessary to clarify the cause of death, which is significance for medico-legal investigation. This article reviewed the latest advancement in the studies on the application of inorganic ions, CK-MB, cTn, ANP and BNP for certification of death from SCD in order to provide a practical way for diagnosis of SCD in forensic pathology.

Biphasic protective effect of oxytocin on cardiac ischemia/reperfusion injury in anaesthetized rats

Oxytocin (OT) is well known for its role in reproduction. However, evidence has emerged suggesting a role in cardiovascular system. The aim of this study was to investigate the cardioprotective effect of oxytocin on ischemia/reperfusion (I/R) injury in an in vivo rat. Myocardial ischemia, was surgically induced by means of left anterior descending coronary artery occlusion for 25 min followed by reperfusion for 120 min. Infarct size was evaluated using the staining agent 2,3,5-triphenyltetrazolium chloride. Creatine kinase-MB isoenzyme (CK-MB) and lactate dehydrogenase (LDH) levels in plasma were analyzed to assess the degree of cardiac injury. Intraperitoneal administration of OT 0.001, 0.01 and 0.1 microg significantly reduced infarct size, LDH and CK-MB levels as compared to control (I/R) group and it had a biphasic effect on the reduction of ischemia/reperfusion injury. This biphasic effect was revealed as a U-shaped curve in which efficacy was optimal between very low and very high doses. Furthermore there were no significant differences in mean arterial pressure or heart rate between the OT treatment groups and control group during I/R. Blockade of specific OT receptors by atosiban (10(-6)M) abolished or attenuated the effect of OT preconditioning. The result of this study shows that OT possess a dose-dependent cardioprotective effect against ischemia/reperfusion injury and so study of OT preconditioning may provide a new target site for therapeutic exploitation.